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Biomedical subjects

W L Webb

Publications and source records attributed to W L Webb.

At least 19 recordsLinked to original sources
PubMed2001

Antibody neutralization of vascular endothelial growth factor inhibits wound granulation tissue formation.

OBJECTIVE: The goal of this work was to test the functional role of vascular endothelial growth factor (VEGF) in promoting the vigorous granulation tissue formation, wound fluid accumulation, and angiogenic responses characteristic of this wound model. BACKGROUND: Formation of vessel-rich granulation tissue is central to wound repair and is thought to be regulated by locally liberated angiogenic factors. Despite the clinical importance of granulation tissue formation in the early stage of wound healing, surprisingly little is known about the molecular identity of signals leading to granulation tissue invasion of a wound space. Methods. A ventral hernia, surgically created in the abdominal wall of 15 swine, was repaired using silicone sheeting and skin closure. An osmotic minipump, inserted in a remote subcutaneous pocket, delivered saline (n = 5), an irrelevant control antibody (n = 5), or neutralizing anti-VEGF antibody (n = 5) into the wound environment. Serial ultrasonography on Days 2, 4, 7, 9, 11, and 14 was used to determine the dimensions of the subcutaneous granulation tissue and wound fluid compartment. VEGF and transforming growth factor beta1 (TGF-beta1) levels in serial wound fluid samples were quantitated by ELISA. On Day 14, animals were sacrificed and the abdominal wall was harvested for histologic, biochemical, and molecular analyses. RESULTS: In animals receiving saline or an irrelevant antibody, a nearly linear 4-fold increase in granulation tissue thickness and 7-fold increase in wound fluid volume were measured over the 14-day study interval. In contrast, in animals receiving anti-VEGF neutralizing antibody, Day 14 granulation tissue thickness and wound fluid volume measurements were essentially unchanged from Day 2 values. Moreover, in the anti-VEGF animals, ultrasonography was unable to resolve the "angiogenic zone" typical of both controls, and correspondingly, wound vessel count and vascular surface area estimates derived from image analysis of histological sections were 3-fold lower in the anti-VEGF animals compared with the saline and antibody controls. Finally, VEGF levels in wound fluid detectable by ELISA analysis were strikingly (10-fold) reduced in anti-VEGF animals on Postsurgery Days 7-14. In contrast, TGF-beta1 levels were unaffected by the anti-VEGF treatment. CONCLUSION: Functional VEGF is a key mediator in wound angiogenesis, fluid accumulation, and granulation tissue formation.

Abdominal Muscles↗
PubMed1993

Three dimensional distribution of needle and stem surface area in a Douglas-fir.

The distribution of needles and branches in the crown of a 14-m tall Douglas-fir was investigated for the purpose of developing a three-dimensional structure for use with radiation transfer models. We found a linear relationship between the basal area of main branches originating at the bole and the total one-sided planimetric surface area of the foliage attached to each branch. A similar linear relationship was found between the branch basal area and the mass of stem material on the branch. Total silhouette area (needles plus branch material) did not vary significantly horizontally along the branch length, but stem surface area declined linearly from near the bole to the branch tip. Needle surface silhouette area and leaf area index increased along the main branch from near the bole to the branch tip. Silhouette leaf area (STAR) did not vary along the main branch. The needle area density (NAD) (m(2) m(-3)) was calculated for each of the lower 11 whorls; the vertical distribution of NAD increased from the base of the bole to the top of the crown.

Journal Article↗
PubMed1983

Psychological sequelae of head trauma.

Head trauma is a significant health care problem. Treatment of the head trauma patient requires assistance from many different disciplines in order to maximize recovery of function. The fact that one fourth or more of head trauma patients are impaired in recovery because of psychological factors suggests that appropriate treatment programs are not being implemented in the United States. Organic factors can produce many of the symptoms reported by head trauma patients. However, these factors are more likely to contribute indirectly to such symptoms, and their influence declines as recovery progresses. Recovery from head trauma follows identifiable stages. During the period of coma, the extent of the organic disturbance is sufficient to impair brain-stem functions. Once consciousness is regained, there is a period of gross memory dysfunction. Coma and posttraumatic amnesia represent the acute phase of recovery, during which patients are often hospitalized and receive intense medical care. Once gross functions return, intense medical care is no longer needed. However, the head trauma victim has not returned to a premorbid status at this point. This phase, between recovery from posttraumatic amnesia and stabilization or recovery of premorbid level of functioning, can best be considered the chronic phase of recovery. The chronic phase of recovery is characterized by defects in cortical functions, including impaired intellectual functions, memory weakness, difficulty in processing complex stimuli, slowed reaction time, and other deficits. While these deficits may not be profound, they do correlate with the severity of injury and the degree of eventual recovery. This observation lends further credence to the presence of underlying disturbance of neurologic functioning. During this chronic phase of recovery, head trauma patients may have made good physical recovery and may feel well enough to return to work. However, they frequently process less information and may experience difficulty with tasks that require attention and effort. Such patients tire rapidly and experience stress symptoms, such as headaches and irritability. These symptoms correspond to environmental demands, but they also reflect underlying neurogenic weaknesses. Emotional sequelae that often emerge during the chronic phase of recovery may be related to the patient's reduced ability to cope with environmental stress. Therefore it is not surprising that emotional sequelae appear to correspond more to environmental demands than to severity of injury per se.(ABSTRACT TRUNCATED AT 400 WORDS)

Amnesia↗
PubMed1982

Psychogenic vomiting: a review.

Psychogenic vomiting appears to be an exacerbation of a longstanding pattern of episodic stress-related vomiting. A small fraction of these patients has serious psychiatric problems and are in need of specialized treatment. Generally, psychogenic vomiters are very resentful of the suggestion that they should seek psychiatric help and more often than not refuse to be referred. Indeed, the majority of these patients is not seriously psychiatrically disturbed. They respond very well to an opportunity to ventilate their stresses to the treating physician and to supportive contacts to help them over their crisis.

Chronic Disease↗
PubMed1980

Improving diagnostic strategies for pain patients.

Any pain experience results from the interaction of biological and functional (namely, psychological and environmental) factors. In some cases functional factors may be primarily responsible for exacerbating and maintaining pain, therefore, the physician should be attentive to a variety of signs that may indicate a significant nonorganic component to the patient's pain. Problems in case management commonly arise when the organic signature is blurred, for pain patients are notoriously resistant to any suggestion that their pain is not purely organic in origin. Clinical experience has shown that the diagnosis and treatment of pain patients can be greatly facilitated by educating the patient about the complex nature of pain and by integrating the assessment of functional factors into the overall diagnostic work-up.

Humans↗